Transcript JAMA Ophthalmology Journal Club Slides: Thickness and Asymmetry After DSAEK Dickman MM, Cheng YYY, Berendschot TTJM, van den Biggelaar FJHM, Nuijts RMMA MD.

JAMA Ophthalmology Journal Club Slides:
Thickness and Asymmetry After DSAEK
Dickman MM, Cheng YYY, Berendschot TTJM, van den Biggelaar
FJHM, Nuijts RMMA MD. Effects of graft thickness and asymmetry on
visual gain and aberrations after Descemet stripping automated
endothelial keratoplasty. JAMA Ophthalmol. Published online April 11,
2013. doi:10.1001/jamaophthalmol.2013.73.
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Introduction
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Descemet stripping automated endothelial keratoplasty (DSAEK) has
become the procedure of choice for treating corneal endothelial disease.
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The main limitation of DSAEK is the proportion of patients achieving 20/20
visual acuity despite clear postoperative corneas and otherwise healthy eyes.
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Recently, attention has been given to the contribution of higher-order
aberrations (HOAs) in degrading optical quality after DSAEK.
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Thinner DSAEK grafts have recently been suggested to achieve better visual
outcomes.
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Objective:
– To investigate the effects of graft thickness and asymmetry on visual gain
and aberrations after DSAEK.
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Methods
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Study Design: Retrospective analysis of an interventional case series.
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Participants: Seventy-nine eyes with corneal endothelial dysfunction.
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Data Analysis:
– Visual gain was defined as the difference between preoperative and
postoperative best-corrected visual acuity in logMAR equivalents.
– Graft thickness was measured centrally using anterior-segment optical
coherence tomography.
– Corneal topography and HOAs were measured by Scheimpflug imaging.
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Limitations:
– Retrospective design.
– Thickness measurements were obtained postoperatively.
– Thickness measurements were limited by axial resolution of anteriorsegment optical coherence tomography (10-20 μm; Visante; Carl Zeiss
Meditec).
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Methods
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Figure 1. Measures of posterior corneal (PC) asymmetry.
Asymmetry of the PC surface was
calculated by fitting raw PC elevation data
against a best-fitted sphere, providing a
measure of donor lenticule asymmetry in
the entire 4- and 6-mm central zones,
analogous to a 3-dimensional graft profile
composed of numerous measurements
across different meridians.
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Results
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Mean best-corrected visual acuity improved from 0.63 logMAR equivalents
preoperatively to 0.25 logMAR equivalents postoperatively (P < .001).
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Mean (SD) graft thickness of the series was 97 (25) μm (range, 39-145 μm).
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Excluding patients with vision-limiting comorbidities, visual gain significantly
correlated with graft thickness (r = −0.35 [P = .02]).
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This correlation was strongest among patients with pseudophakic bullous
keratopathy (PBK) (r = −0.62 [P = .01]).
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Graft thickness significantly correlated with graft asymmetry in the 4-mm and
6-mm zones (r = 0.32 [P = .007] and r = 0.32 [P = .006], respectively), which in
turn correlated with all but spherical PC HOAs.
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Results
Figure 2. Relationship between visual
gain and central graft thickness,
excluding eyes with vision-limiting
comorbidities.
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Figure 3. Relationship between visual
gain and graft thickness among patients
with preoperative PBK.
Results
Figure 4. Relationship between PC
asymmetry and central graft
thickness.
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Figure 5. Relationship between
total PC HOAs and PC
asymmetry.
Comment
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In this study, thinner grafts were associated with greater visual gain in
patients without vision-limiting comorbidities.
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This finding emphasizes the importance of careful patient selection when
considering a more challenging DSAEK procedure using thin donor tissue.
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The correlation between graft thickness and visual gain was strongest in
patients with PBK despite the worse prognosis associated with this
indication.
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This finding is encouraging but should be interpreted with caution owing to
the small number of patients with PBK in this series and the possibility of a
selection bias, as patients with PBK were only referred for DSAEK in the
absence of significant stromal scarring.
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Comment
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A significant correlation was found between graft thickness and PC asymmetry,
which in turn correlated with all but spherical PC HOAs.
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This relationship may be explained by exacerbation of the donor-recipient
curvature mismatch by thicker grafts, resulting in the formation of stromal folds.
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These findings may assist surgeons in choosing DSAEK graft thickness and
shape, particularly in eyes with favorable visual potential.
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Further randomized trials are needed to investigate the relationship between
graft thickness and visual gain after DSAEK.
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Contact Information
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If you have questions, please contact the corresponding author:
– Mor M. Dickman, MD, University Eye Clinic Maastricht, P. Debyelaan 25,
6202 AZ Maastricht, the Netherlands ([email protected]).
Funding/Support
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This study was supported by a grant from ZonMw, the Netherlands
Organization for Health Research and Development.
Conflict of Interest Disclosures
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None reported.
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